ABSTRACT
Guizhou is a subtropical mountainous province, approximately 73% of which is karst areas. The ecosystem in these areas is very fragile and the soil and water losses are extremely severe. In order to protect soil resources, research was conducted from 1991 to 1994. There were five treatments in the experiment: bare land, farmers’ practice, alley cropping (biologically terracing sloping lands), agroforestry, and hillside ditches. The research indicated that, on the sloping upland with gradient of 30 to 40%, the runoff of bare land reached 3778 to 5503 m3 ha'1 yr'1 and the soil loss reached 11,941 t km'2 yr'1. For farmers’ practice, the soil loss was 5778 to 9545 t km'2 yr'1 and the lost nutrients in soil and water averaged 102, 64 and 508 kg ha'1 yr'1 of N, P2O5, and K20, respectively.
